1. Field
The present disclosure relates generally to airdrops and, in particular, to controlling airdrops using wind information. Still more particularly, the present disclosure relates to a method and apparatus for generating predictive wind information for managing airdrops.
2. Background
Airdrops are typically used to deliver cargo to various locations in which other types of cargo delivery systems may not be able to access. For example, airdrops may be used to resupply troops, provide humanitarian aid, deliver equipment, deliver vehicles, and for other suitable purposes.
An airdrop involves delivering cargo through an airdrop system. The airdrop system may include, for example, one or more parachutes attached to a payload. The payload is the cargo to be delivered. An airdrop system also may include a controller that controls the opening of parachutes as well as other components. All airdrop systems are susceptible to errors due to the winds present in the air at the time the airdrop systems make their descent, unless the winds are well-known and stable.
Airdrops may be, for example, high airdrops and low airdrops. A high airdrop is considered to be one made at an altitude in which the region of air that is free from significant ground turbulence effects on a small scale. A low airdrop is one made at an altitude where the dominant influence on the wind is the ground terrain effects. These regions are typically well below the level of mountaintops as air flows in large valleys are generally mostly influenced by the larger scale wind flows.
When performing airdrops at a low enough altitude, other components configured to change the direction at which the airdrop system travels may be cost prohibitive, unnecessary, and impractical. These lower altitudes, such as about 100 feet to about 2,000 feet above ground level, also may involve wind errors due to required rapid deceleration and undesired risks due to gunfire, terrain, and other risks from an altitude.
In other instances, the airdrop may be performed from higher altitudes such as about 5,000 feet above ground level and higher. With these higher altitudes, the accuracy at which cargo may be delivered to a target location may decrease. For example, the wind may affect where the airdrop system lands as the distance to the ground increases.
With these higher altitudes, an airdrop system may include other components such as a computer, a global positioning and inertial navigation system, navigation control software, and other components that may be configured to control the descent of the airdrop system. These components may change the configuration of the parachute to change the path of the airdrop system as it descends toward the target location. The global positioning and inertial navigation system may provide information to calculate the location, direction of travel, and speed of the airdrop system over time. The navigation control software may be used to control the triggers and actuators to direct the airdrop system toward the target location using the information from the global positioning and inertial navigation system. However, wind is still a factor in the final approach for these airdrop systems and impacts the final accuracy beyond desired levels given the cost of the airdrop systems.
Although more sophisticated airdrop systems may provide greater safety, reasonable accuracy in reaching a target location, and have a capability to change the path of the airdrop system as it descends, all airdrop systems are susceptible to errors due to the winds present in the air at the time they make their descent. Sophisticated systems bring with them components that add cost and weight beyond that which is desired.
Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.